861669901 has 4 divisors (see below), whose sum is σ = 862899804. Its totient is φ = 860440000.

The previous prime is 861669869. The next prime is 861669943. The reversal of 861669901 is 109966168.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 600201001 + 261468900 = 24499^2 + 16170^2 .

It is a cyclic number.

It is not a de Polignac number, because 861669901 - 2⁵ = 861669869 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861669971) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 613900 + ... + 615301.

It is an arithmetic number, because the mean of its divisors is an integer number (215724951).

Almost surely, 2^861669901 is an apocalyptic number.

It is an amenable number.

861669901 is a deficient number, since it is larger than the sum of its proper divisors (1229903).

861669901 is a wasteful number, since it uses less digits than its factorization.

861669901 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1229902.

The product of its (nonzero) digits is 139968, while the sum is 46.

The square root of 861669901 is about 29354.2143652321. The cubic root of 861669901 is about 951.5836562592.

The spelling of 861669901 in words is "eight hundred sixty-one million, six hundred sixty-nine thousand, nine hundred one".